Renewable admixtures for cementitious compositions

ABSTRACT

Cementitious compositions comprising a hydraulic cementitious material, a compound selected from the group consisting of a polyhydroxy aromatic compound, a polycarboxylic acid-containing compound or a salt thereof, ascorbic acid or a salt thereof, or a combination thereof, and a particulate material or a water soluble silicate-containing material that interacts with the compound are described herein. The polyhydroxy aromatic compound can be a water soluble compound having from two to thirty hydroxyl groups. The particulate material can exhibit a particle size distribution, wherein at least about 90% by weight of the particles have a diameter of less than 2 mm. Suitable particulate materials include nanoparticles and microparticles. The cementitious compositions can be used to form building materials. The cementitious compositions are especially suited for inhibiting corrosion of reinforcing steel bars embedded in concrete mixtures. Methods of making and using the cementitious composition are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/388,000 filed Apr. 18, 2019 (now U.S. Pat. No. 11,111,178), whichclaims the benefit of and priority to U.S. Patent Application No.62/686,405 filed 5 on Jun. 18, 2018, the disclosures of which are bothexpressly incorporated herein by reference in their entireties.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

This invention was made with Government Support under Grant No. 1563551awarded by the National Science Foundation. The Government has certainrights in the invention.

FIELD

The present disclosure generally relates to cementitious compositions,particularly to the inclusion of renewable materials in cementitiouscompositions to improve the compositions' mechanical properties anddurability.

BACKGROUND

Portland cement has become one of the indispensable primary materials incivil engineering because of its many irreplaceable advantages such asease of application and availability of raw materials. The production ofPortland cement, however, releases a large amount of greenhouse gases.To combat global climate change, the carbon footprint of Portlandcement-based concrete should be reduced. This can be achieved throughenhancing the performance of concrete so that less cement is needed inconcrete or longer service-life of concrete can be reached.

It has been shown that the properties of concrete can be improved byadding another bonding material in addition to cement. Such bondingmaterials include polymeric additives which have been extensivelystudied over last few decades. M. Heidari-Rarania, et al. Constr. Build.Mater. 64 (2014) 308-315; K.-S. Yeon, et al. Constr. Build. Mater. 63(2014) 125-131; and D. Bortzmeyer, et al., J. Mater. Sci. 30 (1995)4138-4144. Polymeric additives, however, are generally based onpetroleum, which are not only nonrenewable and environmentallyunfriendly, but also add considerable cost to the concrete.

There is a need for renewable cementitious materials to combat globalclimate change. The compositions and methods disclosed herein addressthese and other needs.

SUMMARY

In accordance with the purposes of the disclosed systems and methods, asembodied and broadly described herein, the disclosed subject matterrelates to cementitious compositions and methods of making and using thesame. The cementitious compositions can comprise a) a hydrauliccementitious material, b) a hydroxyl containing compound selected fromthe group consisting of a polyhydroxy aromatic compound, apolycarboxylic acid-containing compound or a salt thereof, ascorbic acidor a salt thereof, and a combination thereof and present in an amount offrom 0.1% to 3% by weight, based on the total weight of the cementitiousmaterial, and c) a water soluble silicate-containing material or aparticulate material that can interact with the hydroxy containingcompound. In the cementitious compositions, at least a portion of thehydroxy containing compound is adsorbed to a surface of thewater-soluble silicate-containing material or particulate materialthrough covalent and/or noncovalent interactions.

The hydraulic cementitious material present in the cementitiouscompositions can be selected from Portland cement such as ordinaryPortland cement, calcium aluminate cement, calcium phosphate cement,calcium sulfate hydrate, calcium aluminate sulfonate cement, magnesiumoxychloride cement, magnesium oxysulfate cement, magnesium phosphatecement, and combinations thereof. In specific examples, the hydrauliccementitious material comprises ordinary Portland cement.

The hydroxyl containing compound present in the cementitiouscompositions can be a water soluble compound having two or more hydroxylgroups, such as from two to thirty hydroxyl groups. In some embodiments,the hydroxyl containing compound can have a molecular weight of from 50g/mol to 9000 g/mol, preferably from 50 g/mol to 3000 g/mol. In someexamples, the hydroxyl containing compound can be a polyhydroxy aromaticcompound such as a polyphenol such as a tannin and a proanthocyanidin.An example of a tannin include tannic acid or can be derived from atannin extract such as a vegetable tannin extract. In other examples,the hydroxyl containing compound can include a polyhydroxy phenol suchas catechol, gallic acid, or combinations thereof. In further examples,the hydroxyl containing can include a polycarboxylic acid or a saltthereof, such as citric acid or a salt thereof. In even furtherexamples, the hydroxyl containing can include ascorbic acid or a saltthereof acid. The hydroxyl containing compound can be present in thecementitious compositions in an amount of from 0.1% to 1.5% by weight,preferably from 0.1% to 0.5% by weight, based on the total weight of thecementitious material.

The particulate material that can interact with the hydroxyl containingcompound can have a particle size distribution, wherein at least about90% by weight of the particles have a diameter of less than 2 mm,preferably less than 1 mm, more preferably less than 50 microns, mostpreferably less than 10 microns. For example, the particulate materialcan be selected from nanoparticles, microparticles, or combinationsthereof. Suitable examples of particulate materials that can interactwith the hydroxyl containing compound include silica, clay, fiber,calcium silicate hydrate, calcium aluminate, magnesium oxide, lime,wollastonite, a water soluble silicate salt, or mixtures thereof. Theparticulate material can be present in an amount of from 0.1% to 30% byweight, based on the total weight of the cementitious material and thehydroxyl containing compound. In specific examples, the particulatematerial can comprise nanoparticles, and the nanoparticles can bepresent in an amount of 5% by weight or less, preferably from 0.2% to 5%by weight, more preferably from 0.2% to 3% by weight, based on the totalweight of the cementitious material and the hydroxy containing compound.In other examples, the particulate material can comprise microparticles,and the microparticles can be present in an amount of 30% by weight orless, preferably from 5% to 30% by weight, based on the total weight ofthe cementitious material and the hydroxyl containing compound.

The compositions can include a water soluble silicate containingmaterial such as a water soluble silicate salt. The water solublesilicate salt can be present in an amount of 5% by weight or less,preferably from 0.1% to 5% by weight, more preferably from 0.2% to 3% byweight, based on the total weight of the cementitious material and thehydroxyl containing compound.

The cementitious compositions can include aggregates, that is inaddition to the particulate material or water solublesilicate-containing material that can interact with the hydroxylcontaining compound. Examples of such aggregates include gravel andcrushed stones such as crushed limestone. The cementitious compositionscan be used to make building materials including concrete, tiles,bricks, pavers, panels, or synthetic stones.

Methods of making a cementitious composition comprising mixing ahydroxyl containing compound and a particulate material that caninteract with the hydroxyl containing compound to form a slurry having apH value greater than 4 (such as greater than 5, greater than 6, orgreater than 7), and blending the slurry with a hydraulic cementitiousmaterial to produce a cementitious mixture are disclosed.

Methods of making a cementitious composition comprising mixing ahydroxyl containing compound and a water soluble silicate salt to form asuspension having a pH value greater than 4 (such as greater than 5,greater than 6, or greater than 7), and blending the suspension with ahydraulic cementitious material to produce a cementitious mixture arealso disclosed. The water soluble silicate salt is provided as anaqueous solution and/or can be reacted with an aqueous solution of acalcium salt prior to mixing with the cementitious material. Suitablecalcium salts include calcium nitrate, calcium acetate, calciumchloride, and mixtures thereof.

The methods of making the cementitious compositions described herein canfurther include hydrating the cementitious mixture to form thecementitious compositions. In some embodiments, the cementitiouscompositions can develop a compressive strength that is the same or atleast about 0.1 MPa greater than the compressive strength of anidentical composition not including the hydroxyl containing compound andthe particulate material or silicate-containing material after curingfor 3 days. In some embodiments, the cementitious composition develops acompressive strength of at least about 20% or greater or 10 MPa greaterthan the compressive strength of an identical composition not includingthe hydroxyl containing compound and the particulate material orsilicate-containing material after curing for 28 days.

Methods for improving corrosion resistance of reinforcing steel barsembedded in concrete, comprising embedding the reinforcing steel bars ina cementitious composition described herein are also disclosed.

Additional advantages of the disclosed process will be set forth in partin the description which follows, and in part will be obvious from thedescription, or can be learned by practice of the disclosed process. Theadvantages of the disclosed process will be realized and attained bymeans of the elements and combinations particularly pointed out in theappended claims. It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory only and are not restrictive of the disclosed process, asclaimed.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying figures, which are incorporated in and constitute apart of this specification illustrate several aspects described below.

FIG. 1 is a diagram showing the chemical structure of tannic acid.

FIG. 2 is a diagram showing metal-phenolic networks by coordination oftannic acid and Iron (III), Fe³⁺.

FIG. 3 is a bar graph showing the compressive strength of concretesamples comprising tannic acid.

FIGS. 4A-4B are line graphs showing the heat flow (FIG. 4A) and heatevolution (FIG. 4B) of mortar samples after 72 hours of mixing withtannic acid.

FIGS. 5A-5B are images showing the effect of tannic acid on thedeposition of hydration products on sand. FIG. 5A shows sparse amount ofhydration particles deposited on sand. FIG. 5B shows a dense layer ofhydration particles deposited on sand treated with tannic acid. Whitebar=1 micron.

FIGS. 6A-6B are line graphs showing thermogravimetric analysis (TGA;FIG. 6A) and derivative mass loss (DTG; FIG. 6B) of concrete samplesmixed with tannic acid at 0.3% by weight of the cement after curing for28 days.

FIG. 7 is a bar graph showing the compressive strength of mortar samplescomprising tannic acid and metakaolin.

FIG. 8 is a bar graph showing the compressive strength of mortar samplescomprising tannic acid and silica.

FIG. 9 is a bar graph showing the compressive strength of mortar samplescomprising catechol and silica sol admixture.

FIG. 10 is a bar graph showing the effect of the amount of tannic acidwith sodium silicate solution on the compressive strength development ofcement mortar.

FIG. 11 is a bar graph showing the effect of the amount of tannic acidwith calcium silicate hydrate on the compressive strength development ofcement mortar.

FIG. 12 is a bar graph showing compressive strength of cement mortarcomprising tannic acid and pre-hydrated cement as admixture.

FIG. 13 is a bar graph showing compressive strength of slag-blendedcement mortar comprising tannic acid and silica sol as admixture.

FIG. 14 is a bar graph showing compressive strength of cement mortarcomprising tannic acid and silica sol as admixture.

FIG. 15 is a bar graph showing compressive strength of cement mortarcomprising ascorbic acid or citric acid and sodium silicate solution asadmixture.

DETAILED DESCRIPTION

The materials, compounds, compositions, articles, and methods describedherein can be understood more readily by reference to the followingdetailed description of specific aspects of the disclosed subject matterand the Examples and Figures included therein.

Before the present materials, compounds, compositions, articles,devices, and methods are disclosed and described, it is to be understoodthat the aspects described below are not limited to specific syntheticmethods or specific reagents, as such may, of course, vary. It is alsoto be understood that the terminology used herein is for the purpose ofdescribing particular aspects only and is not intended to be limiting.

Also, throughout this specification, various publications arereferenced. The disclosures of these publications in their entiretiesare hereby incorporated by reference into this application in order tomore fully describe the state of the art to which the disclosed matterpertains. The references disclosed are also individually andspecifically incorporated by reference herein for the material containedin them that is discussed in the sentence in which the reference isrelied upon.

General Definitions

In this specification and in the claims that follow, reference will bemade to a number of terms, which shall be defined to have the followingmeanings:

Throughout the description and claims of this specification the word“comprise” and other forms of the word, such as “comprising” and“comprises,” means including but not limited to, and is not intended toexclude, for example, other additives, components, integers, or steps.

As used in the description and the appended claims, the singular forms“a,” “an,” and “the” include plural referents unless the context clearlydictates otherwise. Thus, for example, reference to “a composition”includes mixtures of two or more such compositions, reference to “anadditive” includes mixtures of two or more such additives, reference to“the cementitious material” includes mixtures of two or more suchcementitious materials, and the like.

“Optional” or “optionally” means that the subsequently described eventor circumstance can or cannot occur, and that the description includesinstances where the event or circumstance occurs and instances where itdoes not.

Ranges can be expressed herein as from “about” one particular value,and/or to “about” another particular value. When such a range isexpressed, another aspect includes from the one particular value and/orto the other particular value. Similarly, when values are expressed asapproximations, by use of the antecedent “about,” it will be understoodthat the particular value forms another aspect. It will be furtherunderstood that the endpoints of each of the ranges are significant bothin relation to the other endpoint, and independently of the otherendpoint. It is also understood that there are a number of valuesdisclosed herein, and that each value is also herein disclosed as“about” that particular value in addition to the value itself. Forexample, if the value “10” is disclosed, then “about 10” is alsodisclosed. It is also understood that when a value is disclosed, then“less than or equal to” the value, “greater than or equal to the value,”and possible ranges between values are also disclosed, as appropriatelyunderstood by the skilled artisan. For example, if the value “10” isdisclosed, then “less than or equal to 10” as well as “greater than orequal to 10” is also disclosed. It is also understood that throughoutthe application data are provided in a number of different formats andthat this data represent endpoints and starting points and ranges forany combination of the data points. For example, if a particular datapoint “10” and a particular data point “15” are disclosed, it isunderstood that greater than, greater than or equal to, less than, lessthan or equal to, and equal to 10 and 15 are considered disclosed aswell as between 10 and 15. It is also understood that each unit betweentwo particular units are also disclosed. For example, if 10 and 15 aredisclosed, then 11, 12, 13, and 14 are also disclosed.

References in the specification and concluding claims to parts by weightof a particular element or component in a composition denotes the weightrelationship between the element or component and any other elements orcomponents in the composition or article for which a part by weight isexpressed. Thus, in a compound containing 2 parts by weight of componentX and 5 parts by weight component Y, X and Y are present at a weightratio of 2:5, and are present in such ratio regardless of whetheradditional components are contained in the compound.

A weight percent (wt %) of a component, unless specifically stated tothe contrary, is based on the total weight of the formulation orcomposition in which the component is included.

Reference will now be made in detail to specific aspects of thedisclosed materials, compounds, compositions, formulations, articles,and methods, examples of which are illustrated in the accompanyingExamples and Figures.

Compositions

Concrete is considered a three-phase composite: bulk cement paste,aggregate, and the interfacial transition zone between the other twophases. Many concrete properties are controlled by the interfacialtransition zone. For example, the interfacial transition zone isconsidered to be the weakest link effecting both durability andmechanical properties of concrete. The bond strength between theaggregate and cement paste in concrete generally provides a strongerinterfacial transition zone. Disclosed herein are cementitiouscompositions comprising renewable additives that enhance bonding withinthe composition thereby providing improved mechanical properties anddurability. In some embodiments, the cementitious compositions comprisea cementitious material, a polyhydroxy aromatic compound, and aparticulate material that can interact with the polyhydroxy aromaticcompound. Methods for making and using the cementitious compositions arealso disclosed herein.

Cementitious Materials

The term “cementitious,” as used herein refers to a binder includingcement; but is not limited to materials traditionally recognized ascements. In some embodiments, the cementitious material can be ahydraulic cement. Hydraulic cement, as used herein, includes materialsthat after combination with water, set and harden as a result ofchemical reactions, even in the presence of excess water. The hydrauliccementitious material can include Portland cement (such as ordinaryPortland cement), alumina cements (such as calcium aluminate cement(CAC)), calcium sulphoaluminate cements (also described assulphoaluminate belite cements such as calcium aluminate sulfonate(CAS)), calcium phosphate cements, calcium sulfate hydrate cements,magnesium oxychloride (MOC) cements, magnesium oxysulfate (MOS) cements,magnesium phosphate cements, pozzolanic slags, fuel ashes, or acombination thereof.

In some examples, the cementitious material can include Portland cement.Portland cement is the most common form of hydraulic cementitiousmaterial. As used herein the term “Portland cement” refers to ahydraulic cement that not only hardens by reacting with water but alsoforms a water-resistant product comprising hydraulic calcium silicates.Portland cement includes Portland cements described in ASTM C150,however, it is to be understood that Portland cement is not limited tothese classes.

In some examples, the cementitious material can include calciumaluminate cement (CAC). CAC is also known in the art as “aluminouscement,” “high-alumina cement,” and “Ciment fondu.” CAC is a uniqueclass of cement that is different from ordinary Portland cement (OPC),particularly due to its chemical make-up. CAC has a high aluminacontent, e.g., greater than 30 wt % up to 80 wt %. During themanufacturing process of CAC, other calcium aluminate and calciumsilicate may be formed, as well as compounds containing relatively highproportions of iron oxides, magnesia, titanic, sulfates, and alkalis.

In some examples, the cementitious material can include calciumaluminate sulfonate (CAS) cement. CAS cements can have variablecompositions, but all of them contain a significant fraction ofYe′elimite, also called Klein's salt or tetracalcium trialuminatesulfate. CAS can also have minor amounts of phases such as C2S, CA,C4AF, CS, CSH2, where C is CaO, S is SiO₂, A is Al₂O₃, F is Fe₂O₃, S isSO₃, M is MgO, T is TiO₂, and H is H₂O.

The cementitious material can include calcium fluoroaluminate (CFA)cement. CFA can have the chemical formula 11CaO·7Al₂O₃·CaF₂. CFA can beused in cold weather.

In some examples, the cementitious material can include calcium sulfatebased cements. Different morphological forms of calcium sulfate can beused in various embodiments of the cementitious compositions. Suitableexamples of calcium sulfate cements include calcium sulfate dihydrate(gypsum), calcium sulfate hemihydrate (stucco), and anhydrous calciumsulfate (sometimes called calcium sulfate anhydrite). These calciumsulfate cements can be from naturally available sources or producedindustrially.

In some examples, the cementitious material can include calcium sulfatehemihydrate (also referred to herein as stucco). Stucco can be made fromflue gas desulfurization—a byproduct of coal combustion.

The cementitious material can include calcium phosphate cement (CPC).CPC comprises one or more calcium orthophosphate powders, which uponmixing with water or an aqueous solution, form a paste that is able toset and harden primarily as hydroxyapatite.

In some examples, the cementitious material can also include magnesiumoxychloride (MOC). MOC cement is also known in the art as “Sorel” or“magnesite”. MOC cement is formed from a magnesium oxide and magnesiumchloride solution.

The cementitious material can include magnesium oxysulphate (MOS). MOScement is formed from magnesium oxide and magnesium sulfate solution.The cementitious material can also include magnesium phosphate cement.Magnesium phosphate cement is a mixture of magnesium oxide andphosphoric acid, which forms water-soluble magnesium dihydrogenphosphate [Mg(H₂PO₄)₂·nH₂O] as a reaction product.

The cementitious material can include one or more of the cementitiousmaterials described herein. For example, the cementitious material caninclude Portland cement only, a Portland cement blend or other hydrauliccements including pozzolanic-lime cements or slag-lime cements. Inregards to the Portland cement blends, it is understood that thePortland cement may contain supplementary cementitious materialsincluding pozzolanic materials, lime, fly ash, mortar, ground granulatedblast furnace slag (GGBS), silica fume, calcined clay, calcined shale,refractory cements, gypsum, expanding cements, sand, rice hull ash,quartz, silica, amorphous silicon dioxide, cement asbestos board (CAB),calcium aluminate cement (CA) or the like. Examples of Portland cementblends include Portland blast-furnace slag cement, Portland-fly ashcement, Portland pozzolanic cement, Portland silica fume cement, masonrycement and expansive cement.

The cementitious material can be present in the cementitiouscompositions in amounts from 5% to 99.9% by weight of the cementitiouscomposition. For example, the cementitious material can be present inthe cementitious composition in an amount of 10 wt % or greater, 20 wt %or greater, 30 wt % or greater, 40 wt % or greater, 50 wt % or greater,60 wt % or greater, 70 wt % or greater, 75 wt % or greater, 80 wt % orgreater, 85 wt % or greater, 90 wt % or greater, 95 wt % or greater, 96wt % or greater, 97 wt % or greater, 98 wt % or greater, 99 wt % orgreater, 99.5 wt % or greater, or 99.7 wt % or greater, based on theweight of the cementitious composition. In some embodiments, thecementitious material can be present in an amount of 99.9 wt % or less,99.5 wt % or less, 99 wt % or less, 98 wt % or less, 95 wt % or less, 90wt % or less, 85 wt % or less, 80 wt % or less, 75 wt % or less, 70 wt %or less, 65 wt % or less, 60 wt % or less, or 55 wt % or less, based onthe weight of the cementitious composition. In some embodiments, thecementitious material can be included in an amount of from 5 wt % to99.9 wt %, from 10 wt % to 99.9 wt %, from 50 wt % to 98 wt %, from 50wt % to 90 wt %, from 60 wt % to 98 wt %, or from 65 wt % to 95 wt %,based on the weight of the cementitious composition.

Hydroxyl Containing Compound

As described herein, the cementitious compositions include a hydroxycontaining compound. The hydroxy containing compound can be naturallyoccurring, synthetic, or combinations thereof. Preferably, the hydroxycontaining compound is naturally occurring. The term. “naturallyoccurring” as used herein refers to a material that can be found and isobtained from nature.

In some embodiments, the hydroxyl containing compound can be apolyhydroxy aromatic compound including a monocyclic or polycyclicpolyhydroxy aromatic compound, which has at least two hydroxyl groups onthe aromatic ring or on at least one of the aromatic rings in apolycyclic compound. In some examples, the polyhydroxy aromatic compoundcan comprise 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 ormore, 8 or more, 9 or more, 10 or more, 11 or more, 12 or more, 13 ormore, 14 or more, 15 or more, 16 or more, 17 or more, 18 or more, 19 ormore, 20 or more, 21 or more, 22 or more, 23 or more, 24 or more, 25 ormore, 26 or more, 27 or more, 28 or more, 28 or more, or 30 or morehydroxyl groups on the aromatic ring or in the polycyclic aromaticcompound. In some examples, the polyhydroxy aromatic compound cancomprise from 2 to 35, from 2 to 30, from 3 to 30, from 5 to 30, from 10to 30, or from 10 to 25 hydroxyl groups on the aromatic ring or in thepolycyclic aromatic compound.

The polyhydroxy aromatic compound can have an aromaticity of greaterthan 50%, such as 60% or greater, 65% or greater, 70% or greater, 75% orgreater, 80% or greater, 85% or greater, 90% or greater, or 95% orgreater by weight of the polyhydroxy aromatic compound. In someembodiments, the polyhydroxy aromatic compound can have an aromaticityof from greater than 50% to 98%, from 60% to 98%, from 75% to 95%, orfrom 95% to 90% by weight of the polyhydroxy aromatic compound. The term“aromaticity” as used herein refers to a chemical property in which aconjugated ring of unsaturated bonds, lone pairs, or empty orbitalsexhibit a stabilization stronger than would be expected by thestabilization of conjugation alone.

In some examples, the polyhydroxy aromatic compound includes monocyclic6-membered-ring aromatic compounds (including carbocyclic andheterocyclic rings) having at least two or at least three hydroxylgroups substituted in the ring. Examples of suitable monocyclic6-membered-ring aromatic compounds include catechol, 1, 2, 3-trihydroxybenzene (pyrogallol) 1, 2, 4-trihydroxy benzene (hydroxyhydroquinone),and 1, 3, 5-trihydroxy benzene (phloroglucinol). The monocyclic6-membered ring aromatic compounds can include substituents other thanhydroxyl groups, examples of which include 2,4,6-trihydroxybenzaldehyde, 2,3,4-trihydroxy acetophenone, 2,4,6-trihydroxyacetophenone, tetrahydroxy-p-quinone dehydrate, 2,3,4-trihydroxy benzoicacid, 3,4,5-trihydroxy benzoic acid (gallic acid), propyl gallate, and2,4,6-trihydroxy benzoic acid.

In some examples, the polyhydroxy aromatic compounds can include apolycyclic aromatic compound having at least three hydroxyl groupssubstituted into one or more of the rings present. In specific examples,the polyhydroxy aromatic compound can include a polyphenol. Examples ofsuitable polyphenol compounds include, for example, purpurogallin,1,2,4-trihydroxy anthraquinone (purpurin), 2,4,6-trihydroxybenzophenone, proanthocyanidins, and tannins. In some examples, thepolyhydroxy aromatic compounds used in the compositions disclosed hereininclude a tannin, a proanthocyanidin, or a combination thereof. Thetannin can be tannic acid and/or derived from a tannin extract such as avegetable tannin extract. Proanthocyanidins are polyphenols and can befound in a variety of plants such as grape seed. Chemically, theproanthocyanidin can be an oligomeric flavonoids, for example, oligomersof catechin and epicatechin and their gallic acid esters. Otherproanthocyanidins can be more complex, having the same polymericbuilding block, and can form tannins. In some examples, the polyhydroxyaromatic compounds can include an oligomeric or polymer flavonoid.

In other embodiments, the hydroxyl containing compound can include aplurality of carboxylic acids. For example, the hydroxyl containingcompound can comprise 1 or more, 2 or more, 3 or more, 4 or more, or 5or more carboxylic acid groups. In some examples, the hydroxylcontaining compound can be a polycarboxylic acid such as citric acid ora salt thereof.

In further embodiments, the hydroxyl containing compound can includeascorbic acid or a salt thereof.

The hydroxyl containing compound can be a weak acid or a weak base. Forexample, the hydroxyl containing compound can have a pKa of 4 orgreater, 4.5 or greater, 5 or greater, 5.5 or greater, 6 or greater, 6.5or greater, 7 or greater, 7.5 or greater, 8 or greater, 8.5 or greater,9 or greater, or 9.5 or greater. In some embodiments, the hydroxylcontaining compound can have a pKa of 12 or less, 11.5 or less, 11 orless, 10.5 or less, 10 or less, 9.5 or less, or 9 or less. In someembodiments, the hydroxyl containing compound can have a pKa of from 4to 12, from 4.5 to 12, from 4.5 to 11, from 5 to 11, from 6 to 11, orfrom 7 to 11. The hydroxyl containing compound for use in thecementitious compositions is preferably a water soluble compound. Insome examples, the hydroxyl containing compound can be soluble in waterat room temperature and pressure (25° C. and 1 atm) in an amount ofgreater than about 40% by weight (e.g., 45% or greater, 50% or greater,55% or greater, 60% or greater, 65% or greater, 70% or greater, 75% orgreater, 80% or greater, 85% or greater, 90% or greater, or 95% orgreater). In some examples, the hydroxyl containing compound can becompletely soluble in water at room temperature. In some embodiments,the hydroxyl containing compound can have a water solubility of greaterthan 1 g/100 g water at 20° C. (for example, 2 g/100 g water or greater,5 g/100 g water or greater, 10 g/100 g water or greater, 15 g/100 gwater or greater, 20 g/100 g water or greater, or 25 g/100 g water orgreater).

The hydroxyl containing compound can have an average molecular weight of50 g/mol or greater (e.g., 100 g/mol or greater, 150 g/mol or greater,200 g/mol or greater, 250 g/mol or greater, 500 g/mol or greater, 550g/mol or greater, 750 g/mol or greater, 800 g/mol or greater, 1000 g/molor greater, 1200 g/mol or greater, 1400 g/mol or greater, 1500 g/mol orgreater, 1800 g/mol or greater, 2000 g/mol or greater, 2500 g/mol orgreater, 3000 g/mol or greater, 3500 g/mol or greater, 4000 g/mol orgreater, 4500 g/mol or greater, 5000 g/mol or greater, 5500 g/mol orgreater, 6000 g/mol or greater, 6500 g/mol or greater, 7000 g/mol orgreater, 7500 g/mol or greater, 8000 g/mol or greater, 8500 g/mol orgreater, or 9000 g/mol or greater). In some cases, the hydroxylcontaining compound have an average molecular weight of 9000 g/mol orless (e.g., 8000 g/mol or less, 7000 g/mol or less, 6000 g/mol or less,5000 g/mol or less, 4000 g/mol or less, 3000 g/mol or less, 2500 g/molor less, 2000 g/mol or less, 1800 g/mol or less, 1600 g/mol or less,1500 g/mol or less, 1200 g/mol or less, 1000 g/mol or less, 800 g/mol orless, or 500 g/mol or less). In some cases, the hydroxyl containingcompound have an average molecular weight of from 50 g/mol to 9000g/mol, from 500 g/mol to 9000 g/mol, from 50 g/mol to 5000 g/mol, orfrom 50 g/mol to 3000 g/mol.

The hydroxyl containing compounds can be present in the cementitiouscomposition in amounts from 0.1% to 5% based on the total weight ofcementitious material. For example, the hydroxyl containing compoundscan be present in an amount of 0.1% or greater, 0.15% or greater, 0.2%or greater, 0.25% or greater, 0.3% or greater, 0.35% or greater, 0.4% orgreater, 0.45% or greater, 0.5% or greater, 1% or greater by weight,1.5% or greater by weight, 2% or greater by weight, 2.5% or greater byweight, 3% or greater by weight, or 3.5% or greater by weight, based onthe total weight of cementitious material. In some embodiments, thehydroxyl containing compounds can be present in an amount of 5% or less,4% or less, 3% or less, 2.5% or less, 2% or less, 1.5% or less, 1% orless, 0.8% or less, 0.7% or less, 0.6% or less by weight, 0.5% or lessby weight, 0.4% or less by weight, 0.35% or less by weight, or 0.3% orless by weight, based on the total weight of cementitious material. Insome embodiments, the hydroxyl containing compounds can be included inan amount from 0.1% to 3% or 0.1% to 1% by weight, based on the totalweight of cementitious material.

Particulate Materials

The cementitious compositions can also include a particulate materialand/or a water soluble material that can interact with the hydroxylcontaining compound. The particulate material can be of varying sizes aswould be understood by those of skill in the art. In some embodiments,the cementitious compositions can include particulate materials definedby a sieve size of 8 or greater, a sieve size of 16 or greater, a sievesize of 30 or greater, a sieve size of 50 or greater, a sieve size of100 of greater, or a sieve size of 200 or greater.

In some examples, the cementitious compositions can include particulatematerials that interact with the hydroxyl containing compound having amedian particle size diameter of 2 mm or less. For example, theparticulate materials that interact with the hydroxyl containingcompound can have a median (D₅₀) particle size diameter of 1.5 mm orless, 1 mm or less, 0.9 mm or less, 0.8 mm or less, 0.75 mm or less, 0.5mm or less, 0.2 mm or less, 0.1 mm or less, 50 microns or less, 30microns or less, 20 microns or less, 10 microns or less, 5 microns orless, 2 microns or less, 1 micron or less, 500 nm or less, 400 nm orless, 200 nm or less, 150 nm or less, 100 nm or less, 75 nm or less, 50nm or less, or 30 nm or less. In some embodiments, the particulatematerials can have a median (D₅₀) particle size diameter of 1 nm ormore, 5 nm or more, 10 nm or more, 20 nm or more, 50 nm or more, 75 nmor more, 100 nm or more, 250 nm or more, 500 nm or more, 1 micron ormore, 2 microns or more, 5 microns or more, 10 microns or more, 50microns or more, 100 microns or more, 500 microns or more, 1 mm or more,1.5 mm or more, or 2 mm or more. In some examples, the particulatematerials can have a median (D₅₀) particle size diameter of from 5 nm to2 mm, from 10 nm to 500 microns, or from 10 nm to 50 microns. Theparticulate materials can have a particle size distribution, wherein atleast 90% by weight of the particles (D₉₀) have a diameter of 2 mm orless (for example, 1.5 mm or less, 1 mm or less, 0.5 mm or less, 0.1 mmor less, 50 microns or less, 10 microns or less, 5 microns or less, 1micron or less, 500 nm or less, 250 nm or less, 100 nm or less, or 50 nmor less). In some embodiments, the particulate materials can have aparticle size distribution, wherein at least 90% by weight of theparticles (D₉₀) have a diameter of from 5 nm to 2 mm, from 10 nm to 500microns, or from 10 nm to 50 microns.

In some embodiments, the cementitious compositions can includenanoparticle sized particulate materials that interact with the hydroxylcontaining compound. The nanoparticles can have a median particle sizediameter of from 1 nm to 1000 nm. For example, the nanoparticles canhave a median particle size diameter of 1000 nm or less, 950 nm or less,900 nm or less, 850 nm or less, 800 nm or less, 750 nm or less, 700 nmor less, 650 nm or less, 600 nm or less, 550 nm or less, 500 nm or less,450 nm or less, 400 nm or less, 350 nm or less, 300 nm or less, 250 nmor less, 200 nm or less, 150 nm or less, 100 nm or less, 75 nm or less,50 nm or less, or 30 nm or less. In some embodiments, the 300 nm orless, 250 nm or less, can have a median particle size diameter of 1 nmor more, 5 nm or more, 10 nm or more, 20 nm or more, 50 nm or more, 75nm or more, 100 nm or more, 150 nm or more, 200 nm or more, 250 nm ormore, 300 nm or more, 350 nm or more, 400 nm or more, 450 nm or more, 50nm or more, or 550 nm or more. In some examples, the nanoparticles canhave a median particle size diameter of from 5 nm to 1000 nm, from 10 nmto 900 nm, from 10 nm to 500 nm, from 10 nm to 400 nm, or from 50 to 500nm.

In some embodiments, the cementitious compositions can includemicroparticle sized particulate materials that interact with thehydroxyl containing compound. The microparticles can have a medianparticle size diameter of from 1 micron to 1000 microns, such as from 1micron to 500 microns, from 2 microns to 200 microns, from 5 microns to50 microns, or from 2 microns to 10 microns.

Suitable examples of particulate materials that interact with thehydroxyl containing compound for including in the cementitiouscompositions can be any natural or synthetic particles. In someexamples, the particulate materials can include inorganic particles.Suitable examples of inorganic particles for use in the cementitiouscompositions can include silica; sand; ground sand; silica fume; slatedust; crusher fines; red mud; amorphous carbon (e.g., carbon black);clays (e.g., kaolin including meta-kaolin); mica; talc; wollastonite;alumina; feldspar; bentonite; quartz; garnet; saponite; beidellite;granite; slag; calcium oxide; calcium hydroxide; antimony trioxide;barium sulfate; magnesium oxide; titanium dioxide; zinc carbonate; zincoxide; nepheline syenite; perlite; diatomite; pyrophillite; flue gasdesulfurization (FGD) material; soda ash; trona; expanded clay; expandedshale; expanded perlite; vermiculite; volcanic tuff; pumice; hollowceramic spheres; hollow plastic spheres; expanded plastic beads (e.g.,polystyrene beads); ground tire rubber; ash, ground/recycled glass(e.g., window or bottle glass); milled glass; glass spheres; glassflakes; fibers; calcium carbonate; aluminum trihydrate (ATH); apolymeric material; and mixtures thereof. In some examples, theparticulate materials can include fibers. The fibers can include glassfibers, basalt fibers, alumina silica fibers, aluminum oxide fibers,silica fibers, carbon fibers, metal fibers, metal and metal-coatedfibers, and mineral fibers (such as stone wool, slag wool, or ceramicfiber wool).

The particulate materials that interact with the hydroxyl containingcompound can be present in the cementitious compositions in amounts from0.1% to 95% by weight of the cementitious composition. For example, theparticulate material can be present in the cementitious composition inan amount of 0.1 wt % or greater, 0.2 wt % or greater, 0.5 wt % orgreater, 1 wt % or greater, 1.5 wt % or greater, 2 wt % or greater, 5 wt% or greater, 10 wt % or greater, 15 wt % or greater, 20 wt % orgreater, 30 wt % or greater, 50 wt % or greater, 60 wt % or greater, 75wt % or greater, or 80 wt % or greater, based on the total weight of thecementitious material and the hydroxyl containing compound. In someembodiments, the particulate material can be present in an amount of 95wt % or less, 90 wt % or less, 85 wt % or less, 80 wt % or less, 75 wt %or less, 50 wt % or less, 45 wt % or less, 30 wt % or less, 25 wt % orless, 20 wt % or less, 15 wt % or less, or 10 wt % or less, based on thetotal weight of the cementitious material and the hydroxyl containingcompound. In some embodiments, the particulate material can be presentin an amount of from 0.1 wt % to 95 wt %, from 0.1 wt % to 50 wt %, from0.1 wt % to 25 wt %, or from 0.5 to 30 wt %, based on the total weightof the cementitious material and the hydroxyl containing compound.

In embodiments where the cementitious compositions include nanoparticlesized particulate materials, the nanoparticle particulate materials canbe present in the cementitious compositions in an amount from 0.1% to30% by weight. For examples, the amount of nanoparticles present in thecementitious compositions can be 0.1% or greater, 0.2% or greater, 0.3%or greater, 0.5% or greater, 1% or greater, 2% or greater, 2.5% orgreater, 3% or greater, 4% or greater, 5% or greater, or 10% or greater,by weight. In some embodiments, the nanoparticles can be present in anamount of 30 wt % or less, 25 wt % or less, 20 wt % or less, 15 wt % orless, 10 wt % or less, 5 wt % or less, 4 wt % or less, 3 wt % or less, 2wt % or less, 1.5 wt % or less, or 1 wt % or less, based on the totalweight of the cementitious material and the hydroxyl containingcompound. In some embodiments, the nanoparticles can be present inamounts from 0.1% to 20% by weight such as from 0.4% to 10% by weight,from 0.2% to 5% by weight, or from 0.2% to 3% by weight, based on thetotal weight of the cementitious material and the hydroxyl containingcompound. In some embodiments, the nanoparticles can include a blendsuch as nanosilica.

In embodiments where the cementitious compositions include microparticlesized particulate materials (such as metakaolin), the microparticleparticulate material can be present in the cementitious compositions inan amount from 5% to 35% by weight. For examples, the amount ofmicroparticles present in the cementitious compositions can be 5% orgreater, 8% or greater, 10% or greater, 15% or greater, 20% or greater,25% or greater, or 30% or greater, by weight. In some embodiments, themicroparticles can be present in an amount of 35 wt % or less, 30 wt %or less, 25 wt % or less, 20 wt % or less, 15 wt % or less, 10 wt % orless, or 5 wt % or less, based on the total weight of the cementitiousmaterial and the hydroxyl containing compound. In some embodiments, themicroparticles can be present in amounts from 5% to 30% by weight suchas from 5% to 25% by weight, or from 5% to 20% by weight, based on thetotal weight of the cementitious material and the hydroxyl containingcompound.

In some examples, the materials that interact with the hydroxylcontaining compound can include a water soluble material. Thewater-soluble material can be a particulate material but dissolvesduring mixing of the cementitious composition and solidify upon curingof the cementitious mixture. Suitable examples of water-solublematerials include, for example, halogen compounds, oxides, silicates,hydroxides, sulfates, carbonates or phosphates of sodium, potassium,calcium, magnesium or iron. In some examples, the material can include awater soluble silicate containing material such as a sodium silicatesalt. The water soluble material can be present in an amount of 5% byweight or less (for example, 4% by weight or less 3% by weight or less,from 0.1% to 5% by weight, from 0.2% to 3% by weight), based on thetotal weight of the cementitious material and the hydroxyl containingcompound.

As described herein, the hydroxyl containing compound can interact withthe particulate material and/or the water soluble material. In someembodiments, at least a portion of the hydroxyl containing compoundsinteract with the particulate material and/or water soluble material.For example, the hydroxyl containing compound can interact with thenanoparticles, microparticles, or water-soluble materials throughcovalent, non-covalent, and/or ionic interactions. In certainembodiments, the hydroxyl containing compound can adhere/adsorb vianon-covalent interactions to a surface of the particulate material(including nanoparticles, microparticles) or water-soluble materialspresent in the compositions. In specific examples, the cementitiouscompositions can include a particulate material that interacts with thehydroxyl containing compound selected from silica, clay, fibers, calciumsilicate hydrate, calcium aluminate, magnesium oxide, lime,wollastonite, a water soluble silicate salt, or mixtures thereof.

The cementitious compositions can also include an aggregate. Theaggregate can be of varying sizes as would be understood by those ofskill in the art. Any aggregate that is traditionally employed in theproduction of cementitious compositions such as concrete compositionscan be used, including dense-graded aggregate, gap-graded aggregate,open-graded aggregate, and mixtures thereof. Dense-graded aggregateexhibits the greatest surface area (per unit of aggregate). Open-gradedaggregate largely consists of a single, large-sized (e.g., around 0.375inch to 1.0 inch) stone with very low levels (e.g., less than about twopercent of the total aggregate) of fines (e.g., material less than 0.25inch) or filler (e.g., mineral material less than 0.075 mm). Gap gradedaggregate fall between dense-graded and open-graded classes.

The compositions disclosed herein can include aggregates and otheradmixtures, as needed depending on the particular application.Aggregates and other admixtures can be added as fillers or tocompositions, such as concrete to modify or influence the hardenedcompositions, such as the workability or compressive strength. Someexamples of aggregates are sand, gravel, or crushed stone. Admixturesmay be added to concrete mixtures for example, to improve stability orto ensure the quality of concrete during mixing, transporting, placing,and curing. Some examples of admixtures include surfactants,crosslinkers, UV stabilizers, fire retardants, antimicrobials,anti-oxidants, and pigments. Examples of UV light stabilizers includehindered amine type stabilizers and opaque pigments like carbon blackpowder. Fire retardants can be included to increase the flame or fireresistance of the compositions. Antimicrobials can be used to limit thegrowth of mildew and other organisms on the surface of the compositions.Antioxidants, such as phenolic antioxidants, can also be added.Antioxidants provide increased UV protection, as well as thermaloxidation protection. Pigments or dyes such as iron oxide can optionallybe added to the compositions described herein.

The cementitious compositions described herein can be used in concrete.Accordingly, concrete compositions comprising the cementitiouscompositions are disclosed. Concrete is most commonly formed fromPortland cement and the concrete is typically manufactured in aready-mix plant. Typically, hydration of Portland cement is acceleratedusing accelerators such as calcium chloride, sodium silicate, sodiumaluminate or aluminium sulphate, or by increasing the fineness of grindof the parent cement. In some cases, the concrete can include a hydroxylcontaining compound, a microparticle or nanoparticle particulatematerial as described herein, and Portland cement and optionally asupplementary cementing material including slaked lime, fly ash,metakaolin, cement kiln dust, blended ordinary Portland cement, groundgranulated blast-furnace slag, limestone fines, or any combinationthereof.

Methods

Methods of preparing the cementitious compositions are also disclosed.In some embodiments, the method can include mixing a cementitiousmaterial, a hydroxyl containing compound, a particulate material and/orwater soluble material that interacts with the hydroxyl containingcompound, and water. The materials can be added in any suitable order.For example, in some embodiments, the mixing stage of the method used toprepare the cementitious compositions can include: (1) mixing thecementitious material, the hydroxyl containing compound, and theparticulate material and/or water soluble material; (2) mixing waterwith the cementitious material, the hydroxyl containing compound, andthe particulate material and/or water soluble material; and (3) allowingthe cementitious mixture to cure. The particulate material and/or watersoluble material that interacts with the hydroxyl containing compoundcan be added at the same time as the hydroxyl containing compound, orcan be added prior to, during, or after stage (1) or (2).

Preferably however, the particulate material and/or water solublematerial that interacts with the hydroxyl containing compound is mixedwith the hydroxyl containing compound prior to stage (1). In someembodiments, the mixing stage of the method used to prepare thecementitious compositions can include: (1) mixing the hydroxylcontaining compound, the particulate material (such as nanoparticles ormicroparticles) or water soluble material), and optionally water; (2)mixing the cementitious material with the hydroxyl containing compound,the particulate material or water soluble material, and optionallywater; (3) optionally mixing water with the cementitious material,hydroxyl containing compound, and the particulate material or watersoluble material; and (4) allowing the cementitious mixture to cure. Asdisclosed herein, the hydroxyl containing compound can react with theparticulate material or water soluble material. The method of making thecementitious compositions disclosed herein can include pre-reacting thehydroxyl containing compound with the particulate material or watersoluble material prior to mixing with the cementitious material.

In specific examples, the method of making the cementitious compositionscan include mixing the hydroxyl containing compound and a particulatematerial that interacts with the hydroxyl containing compound to form aslurry having a pH value greater than 4 (such as greater than 5, greaterthan 6, or greater than 7), and blending the slurry with a hydrauliccementitious material to produce a cementitious mixture.

In other examples, the method of making the cementitious compositionscan include mixing the hydroxyl containing compound and a water solublematerial such as a water soluble silicate salt to form a suspensionhaving a pH value greater than 4 (such as greater than 5, greater than6, or greater than 7), and blending the suspension with a hydrauliccementitious material to produce a cementitious mixture. The watersoluble silicate salt (such as sodium silicate) can be provided as anaqueous solution or mixture. In further examples, the method can includereacting the water soluble silicate salt with a calcium salt (such ascalcium nitrate, calcium acetate, calcium chloride, or mixtures thereof)to form a calcium silicate hydride. The calcium silicate hydride can beformed prior to or during mixing with the hydroxyl containing compound.

The cementitious mixture can be blended in any suitable manner to obtaina homogeneous or heterogeneous blend of the cementitious material,hydroxyl containing compound, and the particulate material or watersoluble material that interacts with the hydroxyl containing compound.In some embodiments, mixing can be conducted in a high speed mixer or anextruder. An ultrasonic device can be used for enhanced mixing and/orwetting of the various components of the compositions. The ultrasonicdevice produces an ultrasound of a certain frequency that can be variedduring the mixing and/or extrusion process. The ultrasonic device usefulin the preparation of compositions described herein can be attached toor adjacent to the extruder and/or mixer. For example, the ultrasonicdevice can be attached to a die or nozzle or to the port of the extruderor mixer. An ultrasonic device may provide de-aeration of undesired gasbubbles and better mixing for the other components, such as particulatematerials.

The pH of the cementitious mixture is greater than 4 (for example,greater than 5, greater than 6, greater than 6.5, greater than 7,greater than 7.5, greater than 8, greater than 8.5, or greater than 9).In some embodiments, the pH of the cementitious mixture is from greaterthan 5 to 12, from 5.5 to 12, from 6 to 12, from 6.5 to 12, from 7 to12, from greater than 7 to 12, from 7.5 to 11, or from 8 to 10.

The method of making the cementitious compositions can include allowingwater, the cementitious material, the hydroxyl containing compound, andthe particulate material or water soluble material to react (or cure) toform a cementitious composite. The composite can have a first surfaceand a second surface opposite the first surface. The curing stage of themethod used to prepare the cementitious composite can be carried out ina mold cavity of a mold, the mold cavity formed by at least an interiormold surface. The mold can be a continuous forming system such as a beltmolding system or can include individual batch molds. The belt moldingsystem can include a mold cavity formed at least in part by opposingsurfaces of two opposed belts. In some embodiments, a molded article canthen be formed prior to the additional method steps in forming thecomposites.

It is desirable that the cementitious compositions has a set-time belowa particular threshold so it can be effectively processed. Withoutwishing to be bound by theory, it is believed that some hydroxylcontaining compounds can retard the compressive strength, especially,the early compressive strength (such as after curing for 3 days or less)of cementitious compositions by its strong adhesion to surfaces throughcovalent and noncovalent interactions. The hydroxyl containing compoundscan be adsorbed to cement particle and hence restrict the access ofwater to cement. In some embodiments, the cementitious compositionsdescribed herein do not exhibit a reduction in its early compressivestrength. In specific embodiments, the cementitious compositionsdescribed herein have a similar or increased compressive strength aftercuring for 3 days compared to an otherwise identical cementitiouscompositions excluding the hydroxyl containing compound. For example,the cementitious compositions described herein have the same, greaterthan 0.5%, greater than 1%, or greater than 5% more compressive strengthafter curing for 3 days compared to an otherwise identical cementitiouscompositions excluding the hydroxyl containing compound. In someembodiments, the cementitious compositions described herein have thesame, greater than 0.1 MPa, greater than 0.5 MPa, or greater than 1 MPamore compressive strength after curing for 3 days compared to anotherwise identical cementitious compositions excluding the hydroxylcontaining compound. The compositions described herein exhibit initialand final set times within the acceptable limits specified by ASTM C94.

Incorporation of the hydroxyl containing compound and the particulatematerial or water soluble material that interacts with the hydroxylcontaining compound into the cementitious compositions can lead toimprovements in the final compressive strength of the cementitiouscompositions. The cementitious compositions comprising the hydroxylcontaining compound and particulate material or water soluble materialdescribed herein have desirably increased compressive strength aftercuring for 28 days, compared to the compressive strength of an otherwiseidentical cementitious composition excluding the hydroxyl containingcompound and the particulate material or water soluble material thatinteracts with the hydroxyl containing compound. In some embodiments,the cementitious compositions described herein have at least 5% morecompressive strength after curing for 28 days compared to an otherwiseidentical cementitious compositions excluding the hydroxyl containingcompound and the particulate material or water soluble material thatinteracts with the hydroxyl containing compound. For example, thecementitious compositions described herein have greater than 5%, greaterthan 10%, greater than 15%, greater than 20%, or greater than 25% morecompressive strength after curing for 28 days compared to an otherwiseidentical cementitious compositions excluding the hydroxyl containingcompound and the particulate material or water soluble material thatinteracts with the hydroxyl containing compound. In some embodiments,the cementitious compositions described herein have greater than 5 MPa,greater than 6 MPa, greater than 8 MPa, greater than 10 MPa, or greaterthan 15 MPa more compressive strength after curing for 28 days comparedto an otherwise identical cementitious compositions excluding thehydroxyl containing compound and the particulate material or watersoluble material that interacts with the hydroxyl containing compound.

In some embodiments, the compressive strength of the cementitiouscompositions described herein can be 60 MPa or greater, after curing for28 days. For example, the compressive strength of the cementitiouscompositions described herein can be 62 MPa or greater, 65 MPa orgreater, 70 MPa or greater, 75 MPa or greater, 80 MPa or greater, 85 MPaor greater, or 90 MPa or greater, after curing for 28 days. In someembodiments, the cementitious compositions can have a compressivestrength of from 60 MPa to 100 MPa or from 60 MPa to 90 MPa, aftercuring for 28 days. The compressive strength can be determined bycylinder specimens as described in ASTM C39 or C39M-18 (2018.

As discussed herein, incorporation of the hydroxyl containing compoundsand the particulate material or water soluble material into thecementitious composites can improve their compressive strength, comparedto when the hydroxy containing compound and particulate material orwater soluble material that interacts with the hydroxyl containingcompound are excluded from the composite. The optimization of thecompressive strength of the composites allows their use in buildingmaterials and other structural applications that is subject to typicalor increased stress of the outdoor environment that surrounds it. Forexample, the composites can be formed into concrete or shaped articlesand used in building materials. Suitable building materials includesiding materials, building panels, sheets, architectural moldings, soundbarriers, thermal barriers, insulation, wall boards, ceiling tiles,ceiling boards, soffits, roofing materials, and other shaped articles.Examples of shaped articles made using the composite panels describedherein include roof tiles such as roof tile shingles, roof cover boards,slate panels, shake panels, cast molded products, moldings, sills,stone, masonry, brick products, posts, signs, guard rails, retainingwalls, park benches, tables, slats, corner arches, columns, ceilingtiles, or railroad ties.

The cementitious compositions described herein can be used to inhibitcorrosion of reinforcing steels embedded within the cementitiouscomposition. Without wishing to be bound to theory, it is believed thatthe hydroxyl containing compound can react with iron, for example, inthe steel and form a dense outer layer on a surface of the steel. Thedense outer layer is resistant to corrosion. Methods for improvingcorrosion resistance of reinforcing steel bars embedded in concrete,comprising embedding the reinforcing steel bars in a cementitiouscomposition as described herein are disclosed.

EXAMPLES

The following examples are set forth below to illustrate the methods andresults according to the disclosed subject matter. These examples arenot intended to be inclusive of all aspects of the subject matterdisclosed herein, but rather to illustrate representative methods andresults. These examples are not intended to exclude equivalents andvariations of the present invention, which are apparent to one skilledin the art.

Efforts have been made to ensure accuracy with respect to numbers (e.g.,amounts, temperature, etc.) but some errors and deviations should beaccounted for. Unless indicated otherwise, parts are parts by weight,temperature is in ° C. or is at ambient temperature, and pressure is ator near atmospheric. There are numerous variations and combinations ofreaction conditions, e.g., component concentrations, temperatures,pressures and other reaction ranges and conditions that can be used tooptimize the product purity and yield obtained from the describedprocess. Only reasonable and routine experimentation will be required tooptimize such process conditions.

Example 1: Bio-Inspired Renewable Admixtures for Concrete

Portland cement-based concrete (PCC) is one of the most widely usedconstruction material in civil infrastructure system, accounting forabout 70% of all building and construction materials. This exampleexplores low-cost natural products, tannic acid (TA), as a new admixtureto enhance both the mechanical properties and durability of OrdinaryPortland Cement (OPC) based mortar/concrete. TA is a water solvableplant polyphenol, and is the world's third largest class of plantcomponents after cellulose and lignin. It can be extracted from plants,microorganisms, or decomposing organic matters in water. One uniquefeature for these biomolecules is their capability to strongly bind todiverse surfaces through covalent and non-covalent interactions. Recentstudies have established that TA can be used to improve the performanceof various materials (B. Horev, et al., ACS Nano 2015, 9, 2390-2404; P.F. Forooshani, et al., Journal of Polymer Science, Part A: PolymerChemistry 2017, 55, 9-33; H. J. Kim, et al., J. Membr. Sci. 2016, 514,25-34; Y. Guan, et al., RSC Adv., 2016, 6, 69966-69972; and S. Yang, etal., Composites Science and Technology 153 (2017), 40-47) through anumber of mechanisms.

Concrete comprising ordinary Portland cement as the binder is one of themost widely used construction material. Although ordinary Portlandcement has many advantages such as ease of application and availabilityof raw materials around the world, the production of ordinary Portlandcement releases a large amount of greenhouse gases. To combat globalclimate change, the carbon footprint of ordinary Portland cement-basedconcrete should be reduced. This can be achieved through enhancing theperformance of concrete so that less ordinary Portland cement is neededin concrete or longer service-life of concrete can be reached.

Concrete comprises granular aggregates and cement paste which bonds theaggregates together. Usually, the aggregates possess better mechanicalproperties and durability than the cement paste, which has anagglomerate structure of calcium silicate hydrates (CSH) and calciumhydroxide (CH) bound together by weak van der Waals forces. Theproperties of the concrete can be improved through enhancing the cementpaste with another bonding material, such as many polymeric additives(M. Heidari-Rarania, et al. Constr. Build. Mater. 64 (2014) 308-315;K.-S. Yeon, et al. Constr. Build. Mater. 63 (2014) 125-131; and D.Bortzmeyer, et al., J. Mater. Sci. 30 (1995) 4138-4144), which have beenextensively studied over last few decades. However, these polymericadditives are based on petroleum, which are not only nonrenewable andenvironmentally unfriendly, but also adds considerable cost to theconcrete.

Daily life observation shows that tea and wine always leave stain on theglassware. The pot used to prepare tea gradually darkens in color, whichis persistent and hard to remove. This interesting feature of teasuggests that some compound in tea has strong bonding ability. Thematerial responsible for the tea staining and tanning has beenidentified as TA (T. S. Sileika, et al. Angew. Chem., Int. Ed. 2013, 52,10766-10770; and S. Quideau, et al. Chem., Int. Ed. 2011, 50, 586-621),which is abundant phenolic dendroid and can be found in wine, tea,coffee, chocolate, tree leaves and barks, and fruits.

The commercially available tannic acid is a plant polyphenol usually canbe written as C₇₆H₅₂O₄₆ with a chemical structure shown in (FIG. 1 ). Ithas a center glucose molecule and five hydroxyl moieties esterified withtwo gallic acid (3,4,5-trihydroxybenzoic acid) molecules. With abundantreactive terminal phenolic hydroxyl groups, tannic acid has ability tocomplex or cross-link macromolecules at multi-binding sites throughmultiple interactions, including hydrogen and ionic bonding andhydrophobic interactions (F. H. Heijmen, et al., Biomaterials 1997, 18,749-754; T. Shutava, et al.; Macromolecules 2005, 38, 2850-2858; and I.Erel-Unal, et al., Macromolecules 2008, 41, 3962-3970).

Recent interest in tannic acid is also inspired by mussels, whichdisplay an extraordinary ability to adhere to substrates under water (J.Guo, et al., Angew. Chem., Int. Ed. 2014, 53, 5546-5551) using adhesiveproteins (J. H. Waite, Chemtech., 1987, 17, 692-697)L-3,4-dihydroxyphenylalanine (DOPA) in the mussel byssus. Waite andTanzer (J. H. Waite, et al. Science 1981; 212:1038-40) found thatcatechols of the DOPA are responsible for the versatile adhesion ofmussels. Studies have also been carried out to exploit catechols asbinding agent in synthetic materials (E. Faure, et al. Progress inPolymer Science 38, 236-270; H. J. Cha, et al., Biotechnology Journal2008; 3:631; J. H. Waite, et al., Science. 1981; 212:1038; and J. J.Wilker, et al., Angewandte Chemie International Edition. 2010; 49:8076).Tannic acid also has high catechol content, and therefore, possesssimilar ability as DOPA to strongly adhere to surfaces through covalentand noncovalent interactions (H. Lee, et al., Proc. Natl. Acad. Sci. USA2006, 103, 12999-13003). Compared with DOPA and its simplified mimic,dopamine, tannic acid is much cheaper and more abundant. For thisreason, the past few years has witnessed applications of tannic acid invarious materials, such as adsorption and antibacterial materials,nano-/microparticles, capsules, films/coatings, bio-adhesive, hydrogels,and nanocomposites (Dierendonck, M. et al., Adv. Funct. Mater. 2014, 24,4634-4644; C. Yang, et al., ACS Appl. Mater. Interfaces 2015, 7,9178-9184; H. Ejima, et al., Science 2013, 341, 154-157; X. Zhang, etal., ACS Appl. Mater. Interfaces 2016, 8, 32512-32519; and H. Fan, etal., Macromolecules 2017, 50, 666-676).

In this example, three salient features of tannic acid have beenexploited to enhance the perforce of concrete.

1) tannic acid can form intermolecular networks cross-linked by hydrogenbonding with a variety of polymers, such as PEG,poly(N-vinylpyrrolidone), poly(N-isopropylacrylamide],poly(N-vinylpyrrolidone) (K. C. Yen et al., Polym. Bull., 2009, 62,225-235; M. Dierendonck, et al., Adv. Funct. Mater., 2014, 24,4634-4644; E. Costa, et al., Macromolecules, 2011, 44, 612-621; and V.Kozlovskaya, et al., Soft Matter, 2011, 7, 2364-2372). Guan et al. (RSCAdv., 2016, 6, 69966-69972), for example, enhanced the tensile strengthand toughness a PVA composite film by 46% and 27%, respectively. Yang etal. (Composites Science and Technology 153 (2017), 40-47) used tannicacid as a self-reinforcing organic filler to prepare nitrile-butadienerubber/tannic acid (NBR/T) composites. It is believed that tannic acidcan be added into concrete to generate a larger number ofstrength-generating bonds, significantly improving the performance ofthe concrete.

2) tannic acid has ability to capture calcium ions and induce localmineralization, as demonstrated in a recent study by Oh et al.(Scientific Reports 2015, 5:10884). Oh et al. immersed tooth sliceswithout and with tannic acid coating in artificial saliva for 7 days toallow hydroxyapatite (HA) to grow on the dentinal tubules. Oh et al.found that no HA was produced on the dentinal tubule of the uncoatedtooth slice, while a lot of needle-like HA minerals can be found on thetubule of tannic acid coated tooth slice. This is because the pyrogallolgroup of tannic acid can bind calcium ions in aqueous environments (S.C. Tam, et al. J. Environ. Qual. 19, 514-520 (1990)), which facilitatesa local supersaturation of Ca²⁺ to induce faster localizedmineralization of HA. Hydration of OPC is nothing but a mineralizationprocess of calcium-contained hydration products such as CSH and CH. Itis speculated that tannic acid can facilitate the hydration of OPC inthe similar fashion as it does on the mineralization of HA shown in FIG.2 .

3) tannic acid can coordinate with metal ions to form TA—metal networks(H. Ejima, et al. Science 2013, 341, 154-157 and T. J. Deming, et al.,Curr Opin Chem Biol 3 (1) (1999) 100-105). TA is coordinated to 18different metal ions, including aluminum and iron (J. Guo, et al.,Angew. Chem., Int. Ed. 2014, 53, 5546-5551). Its adjacent hydroxylgroups provide chelating sites for Al³⁺ or Fe³⁺ ions. Together with theefficient coordination-driven cross-linking facilitated by the largenumber of gallol groups, a three dimensionally stabilized metal-phenolicnetworks (MPNs) can be produced, as shown in FIG. 2 . Since both Al³⁺and Fe³⁺ are present in OPC in tricalcium aluminate (C3A) andtetracalcium aluminoferrite (C4AF), it is anticipated that MPNs can beformed in concrete, strengthening the concrete. More importantly, tannicacid can react with steel to form a crazed layer of ferric tannates,which serves as an electrical insulator to inhibit the corrosion of thesteel (M. Dierendonck, et al. and E. Costa, et al.).

The inherent abilities of TA outlined above, the low-cost, renewable,and non-toxic nature of TA, TA provides an environmentally friendlysolution to enhance the performance of OPC based concrete.

Experimental: concrete cylinder specimens (4″×8″) were made as controlgroup according to ASTM C192 (ASTM C192/C192M-16a Standard Practice forMaking and Curing Concrete Test Specimens in the Laboratory, 2016) usingSAKRETE™ type I/II Portland cement, water, and standard graded fine andcoarse aggregate at mass ratio of 193:362:842:1022. Based on Boguecalculation (ASTM C150, Standard Specification for Portland Cement,2007), this cement has 53% C3S, 25.7% C25, 8.6% C₃A, and 7.8% C₄AF. Thefine aggregates were river sand with bulk specific gravity of 2.70 andwater absorption capacity of 0.95%. The coarse aggregates were crushedlimestone with dry specific gravity of 2.74 and water absorptioncapacity of 0.7%. Another two group of samples were made with the samemix as the control group but adding tannic acid at 0.1% and 0.3% (inweight) of the cement, respectively. The compressive strengths of thesesamples were measured after standard curing of 3 days, 7 days and 28days, respectively, as shown in FIG. 3 . In this figure, TA-1 and TA-3refers to the concrete samples with 0.1% and 0.3% of TA (tannic acid),respectively. Adding 0.1% TA slightly increases the compressive strengthof the concrete at all ages in comparison with the control group.Increasing the TA content to 0.3% of the cement reduces the compressivestrength of the sample at 3 days, but improves the compressive strengthat 7 and 28 day by 25% and 23%, respectively. However, such asignificant increase on compressive strength achieved by just adding0.3% TA challenges the common belief, which states that adding TA inmixing water reduces the compressive strength of the concrete, as shownin S. H. Kosmatk, et al. (Design and Control of Concrete Mixtures,EB001, 15^(th) Ed, Portland Cement Association, 2011, 460 pages).

The discrepancy between the results in this example and Kosmatk et al.is believed to be due to the dose of TA added into the mixing water. Theretarding effect of the TA can be alleviated by reducing its dose. Forexample, reducing the dose of TA to 0.3%, the retarding effect of the TAonly slightly reduces the compressive strength of the concrete at 3 daysas shown in FIG. 3 . Further reducing the dose of the TA to 0.1%, noretarding effect on the strength developed can be observed from FIG. 3 .

The retarding effect of TA is also revealed by the set times of theconcrete without TA and the one with 0.3% TA shown in Table 1. Theinitial and final set times of the concrete were extended from 144 min.and 200 min. to 270 min. and 565 min., respectively, exceeding theacceptable limits specified by ASTM C94 (ASTM C94/C94M-16b StandardSpecification for Ready-Mixed Concrete, 2016). Isothermal calorimetrytest based on ASTM C1679 (ASTM C1679-17 Standard Practice for MeasuringHydration Kinetics of Hydraulic Cementitious Mixtures Using Isothermalcalorimetry, PA, 2017) and ASTM C1702 (ASTM C1702-17 Standard TestMethod for Measurement of Heat of Hydration of Hydraulic CementitiousMaterials Using Isothermal Conduction calorimetry, PA, 2017) was carriedout on two cement pastes with water to cement ratio of 0.4 to furtherexamine the retarding effect of TA. The control shown in FIGS. 4A-4Brefers to the paste without adding TA and the TA-2 group refers to thepaste with 0.2% TA. As shown in FIG. 4A, two peaks which are induced bythe hydration of tricalcium silicate (C3S) and tricalcium aluminate(C3A) can be clearly identified on heat flow of the control sample.After adding 0.2% of TA, these two peaks were delayed and drasticallyreduced, as shown in FIG. 4A, confirming the significant retardingeffect of TA on the hydration of the cement at the early age. FIG. 4Bshows that the total heat released from the paste with 0.2% TA onlyreaches ⅔ of that released from the control group at 72 h.

TABLE 1 The set time of the paste with different amounts of TA andCa(OH)₂. Control TA-3 TAC-3 TA Dose  0 0.3 wt. % 0.3 wt. % Ca(OH)₂ (g) 0  0 0.075 Initial (min) 144 270 190 Final (min) 200 565 290

The strong retarding effect of the TA is believed to be induced by itsstrong adhesion to surfaces through covalent and noncovalentinteractions. It can be adsorbed to cement particle and hence restrictsthe access of water to cement. This retarding effect can be alleviatedor eliminated if TA is adsorbed on small particles before being addedinto the mix of the concrete. To verify this idea, a small amount ofcalcium hydroxide (CH) powder was added into the mixing water beforemixing with 0.2% TA (in weight of cement) so that TA can be adsorbedonto CH powders. The produced CH coated with TA suspension was thenmixed with the cement to produce cement paste with the same water tocement ratio of those pastes tested in FIG. 3 . The calorimetry testingresult of this paste is shown in FIG. 4 and referred to as CH+TA_2. Theretarding effect of the TA is almost eliminated by this method asrevealed by this figure. Two peaks corresponding to the hydration of C₃Sand C₃A were only slightly delayed and the total hydration heat of thepaste reaches more than 90% of the control one during the measuringperiod. The effectiveness of this method to mitigate the retardingeffect of the TA can be further verified by the set time of the concretemade with TA first adsorbed to CH, as shown in Table 1. In this table,the group TAC_3 was made in the same way as the TA-3 group except thatthe TA was adsorbed to CH by adding 1% (of cement) CH to the TA solutionbefore being mixed with other ingredients of the concrete. As a result,the initial and final set times were reduced to 190 min. and 290 min.,respectively, which are acceptable according to ASTM C94. Moreinterestingly, this method of alleviating the retarding effect of the TAappears to have no significant effect on the strength improvementinduced by the TA, as shown in FIG. 3 . The compressive strength of theTAC-3 group at 3 days is slightly higher than that of the TA-3 becauseof the reduced retarding effect of TA after adsorbed to CH particles.

In summary, this example confirms significant enhancement on themechanical properties of concrete can be achieved by adding small amountof TA as additive. The retarding effect of the TA can be alleviated oreliminated by adsorbing TA to small particles before added into theconcrete mix.

Without wishing to be bound by theory, it is believed that themechanisms responsible for the enhancement induced by the TA, may be dueto TA initiating local mineralization and anchoring the hydrationproducts. As a polyphenol, TA is known to strongly bind to diversesurfaces through covalent and non-covalent interactions. As demonstratedin this example, TA can be either directly added or first adsorbed tosome particles and then added into the concrete. In both cases, TA isdeposited on some surfaces which can be the surface of the un-hydratedcement particles, or the surface of hydrates, or aggregates. Thepyrogallol groups of TA can strongly capture calcium ions released fromthe cement particles, creating a local supersaturation of Ca²⁺,initiating precipitation of hydration products such as CSH and CH onthis surface. In this way, TA turns an arbitrary surface in concreteinto nucleating sites for hydration products, facilitating the hydrationof the OPC. More importantly, these hydration products are firmlyanchored to the surface by the TA due to its strong binding ability,leading to higher mechanical strength.

To provide preliminary support to this hypothesis, two quartz sandsamples were prepared, a control sample without soaking in 1% TAsolution and a treated sample produced by soaking in the 1% TA solutionfor 6 h. These two sand samples were immersed into a solution of 0.05mol/L (CH₃COO)₂Ca and 10 g Na₂SiO₃-9H₂O for 24 h to allow for thedeposition of CSH on them. SEM image shows that very little precipitatewas deposited on the surface of the control sample, as shown in FIG. 5A.While a uniform layer of precipitate was produced on the surface of thesand treated by soaking in TA solution, as shown in FIG. 5B. The sharpdifference between these two sand samples is clearly attributed to theability of TA to capture calcium, which induces CSH to precipitate onthe surface of the sand.

Thermogravimetric analysis (TGA) on two concrete samples tested in FIG.3 was conducted and results are shown in FIGS. 6A-6B. In this figure,the C-28 groups refers to the control concrete sample without using TAat 28 days and the TA3-28 refers to the one with 0.3% of TA at 28 days.Four main peaks appear on the derivative mass loss (DTG) graph of thesetwo samples FIG. 6B, corresponding to the decomposition of ettringite,CH and calcite, respectively. The typical decomposition temperatureranges for ettringite, AFm, CH and calcium carbonate are 80° C.-130° C.,180° C.-200° C., 400° C.-500° C., and 680° C.-780° C., respectively.Adding TA doesn't increase the amount of CH in the concrete specimen,but significantly increases the amount of calcium carbonate in theconcrete, as shown in FIG. 6B. The calcium carbonate present in bothconcrete samples were very likely resulted from the carbonation of CH inthe air. It was noticed that both samples were ground and dried in openair. If this is the case, the total CH produced in the sample with TAwill be higher than that produced in the control sample, suggesting thatTA can promote hydration of the cement due to the seeding effect of TA.

Without also wishing to be bound by theory, it is believed that themechanisms responsible for the enhancement induced by the TA, may be dueto strengthening hardened paste through TA-metal chelation. Metalchelation is a common feature for many polyphenols. TA possesses manygalloyl groups which provide binding sites for metal ions to chelate.After adding into concrete, TA can form TA—metal linkage with Al³⁺ andFe³⁺ ions released from C₃A and C₄AF in OPC. This linkage can existbetween any solid particles in the concrete, providing bonding force inaddition to the van der Waals force between the hydration products. Athree dimensionally metal-phenolic networks can also be possiblyproduced in the concrete by TA.

The above strengthening mechanism obtained by TA-metal chelation is alsoadopted by living organisms to achieve a number of desirable materialproperties, such as increased toughness, self-repair, adhesion, highhardness in the absence of mineralization, and mechanical tunability.For example, although the cuticles of marine mussels is largelyproteinaceous, it is approximately five times harder than the threadcore. A recent study discovered that the catechoto—iron chelatecomplexes crosslinking protein granules are responsible for this highhardness of the cuticles. This biologically inspired strengtheningstrategy through metal complexation crosslinking has also beensuccessfully used to tune both the strength and toughness of spidersilks.

With large amount of phenolic hydroxyl groups, TA can also form a largenumber of hydrogen bonds within concrete, which significantly improvethe performance of the concrete. As a result, the mechanical propertiesof the concrete can be greatly improved.

Without further wishing to be bound by theory, it is believed that themechanisms responsible for the enhancement induced by the TA, may be dueto densifying the microstructure of the hardened concrete. As mentionedabove, TA converts various surface into nucleation sites for theprecipitation of CSH and CH out of the pore solution, filling the gapbetween cement particles. As a result, capillary porosity of the mortaris reduced, leading to a denser microstructure and higher compressivestrength. Without the nucleating effect of TA, larger capillary porositywill be formed.

Example 2: TA Used Together with Metakaolin TA

TA can be used together with metakaolin (MK) as admixture for concrete.Table 2 shows the mix of three concrete mortar samples made without andwith TA and metakaolin admixture. The strength of these samples areshown in FIG. 7 . It can be seen that the compressive strength of thecement mortar has been improved nearly 70% by using the TA andmetakaolin as admixture.

TABLE 2 Mix proportions (g) of concrete with metakaolin and TA asadmixture Soaking Cement MK Water Sand TA Control 1045  — 550 2860 MK-C836 209 550 2860 MK-TA 836 209 550 2860 YES

Example 3: TA Used Together with Colloidal Silica

TA can be used together with colloidal nanosilica as admixture forconcrete. Table 3 shows the mix of four concrete mortar samples madewithout TA or colloidal silica, with colloidal silica only, with TAonly, and with TA and colloidal nanosilica admixture. The strength ofthese samples are shown in FIG. 8 . It can be seen that the compressivestrength of the cement mortar at 28 days has been improved 36% by usingthe TA and colloidal nanosilica as admixture.

TABLE 3 Mix proportions (g) of cement mortar with TA and nanosilica asadmixture Colloidal Cement nano-SiO₂ TA Water Sand Control 1097 — — 5502860 SiO₂ − TA 1045 50 — 500 2860 TA 1097 — 2.2 550 2860 SiO₂ + TA 104550 2.2 500 2860

Example 4: Catechol Used Together with Silica Sol

Catechol was used together with silica sol as admixture for concrete.Table 4 shows the mix of four concrete mortar samples made withoutcatechol or silica sol, with silica sol only, with catechol only, andwith catechol and silica sol admixture. The strength of these samplesare shown in FIG. 9 . It can be seen that the compressive strength ofthe cement mortar at 28 d has been improved up to 25% by using thecatechol and silica sol as admixture.

TABLE 4 Mix proportions (g) of cement mortar with catechol and colloidalnanosilica as admixture Colloidal Cement nano-SiO₂ Catechol Water Sand*Control 1095 — — 550 2860 SiO₂ 1045 50 — 500 2860 Catechol 1095 — 2 5502860 Catechol + 1045 50 2 500 2860 SiO₂ *The sand is manufactured sand,not natural sand.

Example 5: Tannic Acid Used Together with Sodium Silicate Solution

Tannic acid was used together with sodium silicate (water glass (WG)) asadmixture for concrete. Table 5 shows the mix of concrete mortar samplesmade without TA or sodium silicate, with sodium silicate only, and withsodium silicate solution and different contents of TA as admixture.Tannic acid was first mixed with the sodium silicate solution to make asuspension and then mixed with the remaining ingredients of the mortar.The strength of each sample is shown in FIG. 10 . It can be seen thatthe compressive strength of the cement mortar at 28 d has been improvedup to 35% by using the TA and sodium silicate as admixture.

TABLE 5 Mix proportions (g) of cement mortar with tannic acid and sodiumsilicate solution as admixture Cement Water Sand Na₂SiO₃ TA Control 1045550 2860 — — Na₂SiO₃(12) 1040 543 2860 12 — Na₂SiO₃(12) + 1040 543 286012 2 0.2% TA Na₂SiO₃(12) + 1040 543 2860 12 4 0.4% TA Na₂SiO₃(12) + 1040543 2860 12 6 0.6% TA

Example 6: Tannic Acid Used Together with Calcium Silicate Hydrate (CSH)Particles

Tannic acid was used together with in-situ produced calcium silicatehydrate particles as admixture for concrete. Table 6 shows the mix ofconcrete mortar samples made without TA or CSH, with CSH only, and withCSH and different contents of TA as admixture. Tannic acid was firstmixed with the sodium silicate solution and calcium nitrate to make asuspension of CSH, which was then mixed with the remaining ingredientsof the mortar. The strength of these samples are shown in FIG. 11 . Itcan be seen that the compressive strength of the cement mortar at 28 dhas been improved 37% by using the TA together with CSH as admixture.

TABLE 6 Mix proportions (g) of cement mortar with tannic acid and CSH asadmixture Cement Water Sand Na₂SiO₃ Ca(NO₃)₂ TA Control 1045 550 2860 —— CSH(6) 1039 543 2860 12 4.74 — CSH(6) + 0.1% TA 1039 543 2860 12 4.741 CSH(6) + 0.2% TA 1039 543 2860 12 4.74 2 CSH(6) + 0.3% TA 1039 5432860 12 4.74 3 CSH(6) + 0.5% TA 1039 543 2860 12 4.74 5 CSH(9) 1036 5402860 18 7.11 — CSH(9) + 0.2% TA 1036 540 2860 18 7.11 2

Example 7: Tannic Acid Used Together with Pre-Hydrated Cement Particles

Tannic acid was used together with pre-hydrated cement particles asadmixture for concrete. Table 7 shows the mix of concrete mortar samplesmade without TA or pre-hydrated cement particles, with 0.5% pre-hydratedcement particle, and with 0.5% pre-hydrated cement particles togetherwith different contents of TA as admixture. The pre-hydrated cement andtannic acid suspension was made by mixing the tannic acid with 0.5%(weight of total cement) in water under stirring at rpm 900 for 6 hours.The produced suspension was then mixed with the remaining ingredients ofthe mortar. The strength of these samples are shown in FIG. 12 . It canbe seen that the compressive strength of the cement mortar at 28 d hasbeen improved up to 31.43% by using the TA and the pre-hydrated cementparticles.

TABLE 7 Mix proportions (g) of cement mortar with tannic acid andpre-hydrated cement as admixture Pre-hydration TA amount* (wt % Cement(wt % of of Water Sand (g) cement) cement) (g) (g)** P0-0 1068 0.5 — 5873243 P0-C 1068 — — 587 3243 P0-T0.25 1068 0.5 0.025 587 3243 P0-T0.51068 0.5 0.05  587 3243 P0-T1 1068 0.5 0.1   587 3243 P0-T3 1068 0.50.3   587 3243 P0-T5 1068 0.5 0.5   587 3243 P0-T10 1068 0.5 1     5873243

Example 8. Tannic Acid Used Together with Silica Sol for Slag BlendedCement Mortar

Tannic acid was used together with silica sol as admixture forslag-blended Portland cement concrete. Slag is a supplementarycementitious material which can be used to partially replace Portlandcement in concrete. Table 8 shows the mix of 20% slag-blended concretemortar samples made without TA or silica sol, with tannic acid only,with 5% (in weight of cement) silica sol only, and with 5% (in weight ofcement) silica sol and TA. The strength of these samples are shown inFIG. 13 . It can be seen that the compressive strength of theslag-blended cement mortar at 28 d has been improved 26% by using the TAand silica sol as admixture.

TABLE 8 Mix proportions (g) of slag blended cement mortar with TA andsilica sol as admixture Cement Slag TA Silica-sol Water Sand (g) (g) (g)(g) (g) (g)** S2-C 880 220 — — 550 2960 S2-T2 880 220 2.2 — 550 2960S2-S5 880 220 — 50 550 2960 S2-T2S5 880 220 2.2 50 550 2960 *TA andcolloidal nano-SiO₂ are solved in DI water separately and then mixedtogether. **The sand is manufactured sand, not natural sand.

Example 9. Tannic Acid Used Together with Silica Sol for Fly Ash BlendedCement Mortar

Tannic acid was used together with silica sol as admixture for flyash-blended Portland cement concrete. Fly ash is a supplementarycementitious material for concrete which can be used to partiallyreplace Portland cement in concrete. Table 9 shows the mix of 20% flyash-blended concrete mortar samples made without TA or fly ash, withtannic acid only, with 5% (in weight of cement) silica sol only, andwith 5% (in weight of cement) silica sol and TA. The strength of thesesamples are shown in FIG. 14 . It can be seen that the compressivestrength of the slag-blended cement mortar at 28 d has been improved 44%by using the TA and silica sol as admixture.

TABLE 9 Mix proportions (g) of fly ash-blended cement mortar with TA andsilica sol as admixture Class F Cement Fly Ash TA Silica sol Water Sand(g) (g) (g) (g)* (g) (g)** F2-C 880 220 — — 550 2960 F2-T2 880 220 2.2 —550 2960 F2-S5 880 220 — 50 550 2960 F2-T2S5 880 220 2.2 50 550 2960 *TAand silica sol are solved in DI water separately and then mixedtogether. *The sand is manufactured sand, not natural sand.

Example 10: Ascorbic Acid (Vitamin C) and Citric Acid Used Together withSodium Silicate Solution

Ascorbic acid and citric acid were used together with sodium silicate(water glass (WG)) as admixture for concrete. Table 10 shows the mix ofconcrete mortar samples made without ascorbic acid or citric acid(control group), with citric acid and water glass, with ascorbic acidonly, and with ascorbic acid and sodium silicate solution as admixture.Ascorbic acid or citric acid was first mixed with the sodium silicatesolution to make a suspension and then mixed with the rest ingredientsof the mortar. The strength of these samples are shown in FIG. 15 . Itcan be seen that the compressive strength of the cement mortar at 28 dhas been improved 21% by using the citric acid and sodium silicate asadmixture, and 22% by ascorbic acid and sodium silicate solution.

TABLE 10 Mix proportions (g) of citric acid or ascorbic acid blendedcement mortar with and sodium silicate solution as admixture CementWater Sand Na₂SiO₃ CA* AA* Control 1045 550 2860 — — — CA + WG 1040 5432860 12 2 — AA** 1045 540 2860 — — 2 AA + WG 1040 540 2860 12 — 2 *WG:water glass/CA: Citric acid/AA: Ascorbic acid. **delayed setting

The materials and methods of the appended claims are not limited inscope by the specific materials and methods described herein, which areintended as illustrations of a few aspects of the claims and anymaterials and methods that are functionally equivalent are within thescope of this disclosure. Various modifications of the materials andmethods in addition to those shown and described herein are intended tofall within the scope of the appended claims. Further, while onlycertain representative materials, methods, and aspects of thesematerials and methods are specifically described, other materials andmethods and combinations of various features of the materials andmethods are intended to fall within the scope of the appended claims,even if not specifically recited. Thus a combination of steps, elements,components, or constituents can be explicitly mentioned herein; however,all other combinations of steps, elements, components, and constituentsare included, even though not explicitly stated.

What is claimed is:
 1. A composition, comprising: a hydrauliccementitious material; a hydroxyl containing compound comprising apolyhydroxy aromatic compound having three or more hydroxyl groups;wherein the hydroxyl containing compound is present in an amount of from0.1% to 3% by weight, based on the total weight of the cementitiousmaterial; and a water soluble silicate-containing material in an amountof from 0.1% to 5% by weight, based on the total weight of thecementitious material and the hydroxyl containing compound, wherein thewater soluble silicate-containing material interacts with the hydroxylcontaining compound.
 2. The composition of claim 1, wherein thehydraulic cementitious material is selected from the group consisting ofordinary Portland cement, calcium aluminate cement, calcium phosphatecement, calcium sulfate hydrate, calcium aluminate sulfonate cement,magnesium oxychloride cement, magnesium oxysulfate cement, magnesiumphosphate cement, and combinations thereof.
 3. The composition of claim1, wherein the polyhydroxy aromatic compound is water soluble.
 4. Thecomposition of claim 1, wherein the polyhydroxy aromatic compound has amolecular weight of from 50 to 9000 g/mol.
 5. The composition of claim1, wherein the polyhydroxy aromatic compound is a polyphenol, apolyhydroxy phenol, or a combination thereof.
 6. The composition ofclaim 1, wherein the polyhydroxy aromatic compound comprises a tannin, aproanthocyanidin, a gallic acid, or a combination thereof.
 7. Thecomposition of claim 1, wherein the polyhydroxy aromatic compound ispresent in an amount of from 0.1% to 1.5% by weight, based on the totalweight of the cementitious material.
 8. The composition of claim 1,wherein at least a portion of the hydroxyl containing compound reactswith a surface of the water soluble silicate-containing material throughcovalent and/or noncovalent interactions.
 9. The composition of claim 1,further comprising an aggregate.
 10. A method of making a cementitiouscomposition according to claim 1, the method comprising: mixing thehydroxyl containing compound the water soluble silicate-containingmaterial that interacts with the hydroxyl containing compound, and thehydraulic cementitious material to produce a cementitious mixture,wherein the hydroxyl containing compound is present in an amount of from0.1% to 3% by weight, based on the total weight of the cementitiousmaterial and the hydroxyl containing compound.
 11. The method of claim10, further comprising hydrating the cementitious mixture.
 12. Themethod of claim 10, wherein the cementitious composition after curingfor 3 days, develops a compressive strength that is the same or at leastabout 0.1 MPa greater than the compressive strength of an identicalcomposition not including the hydroxyl containing compound and the watersoluble silicate-containing material.
 13. The method of claim 10,wherein the cementitious composition after curing for 28 days, developsa compressive strength of at least about 20% or greater or at leastabout 10 MPa greater than the compressive strength of an identicalcomposition not including the hydroxyl containing compound and the watersoluble silicate-containing material.
 14. A method for improvingcorrosion resistance of reinforcing steel bars embedded in concrete,comprising: embedding the reinforcing steel bars in a cementitiouscomposition according to claim
 1. 15. A building material selected fromconcrete, a tile, a brick, a paver, a panel, or a synthetic stonecomprising the cementitious composition of claim
 1. 16. The compositionof claim 1, wherein the hydroxyl containing compound comprises tannicacid.
 17. The composition of claim 1, further comprising a particulatematerial, wherein the particulate material interacts with the hydroxylcontaining compound.
 18. The composition of claim 17, wherein at least aportion of the hydroxyl containing compound reacts with a surface of theparticulate material through covalent and/or noncovalent interactions.19. The composition of claim 17, wherein at least about 90% by weight ofparticles in the particulate material have a diameter of less than 2 mm.20. The composition of claim 17, wherein the particulate materialcomprises silica, clay, fibers, calcium silicate hydrate, calciumaluminate, magnesium oxide, lime, wollastonite, a water soluble silicatesalt, or mixtures thereof.
 21. The composition of claim 17, wherein theparticulate material comprises: nanoparticles present in an amount offrom 0.2% to 5% by weight, based on the total weight of the cementitiousmaterial and the hydroxyl containing compound; microparticles present inan amount of from 5% to 30% by weight, based on the total weight of thecementitious material and the hydroxyl containing compound; or acombination thereof.
 22. A method of making a composition, the methodcomprising: mixing a hydroxyl containing compound and a particulatematerial that interacts with the hydroxyl containing compound to form aslurry having a pH value higher than 4, and blending the slurry with ahydraulic cementitious material to produce a cementitious mixture;wherein the hydroxyl containing compound is selected from the groupconsisting of: a polyhydroxy aromatic compound having three or morehydroxyl groups; ascorbic acid or a salt thereof; and a combinationthereof; wherein the hydroxyl containing compound is present in anamount of from 0.1% to 3% by weight, based on the total weight of thecementitious material.
 23. The method of claim 22, the method furthercomprising mixing the hydroxyl containing compound with a water solublesilicate salt or Portland cement particles.
 24. The method of claim 23,further comprising reacting the water soluble silicate salt with anaqueous solution of a calcium salt.